GUARD AS 1595977 - Caterpillar

Illustration 1 g01197068
Schematic for the Lift Lower Solenoid This diagnostic code is recorded when the ECM detects a incomplete electrical path. The electrical path from the ECM to the solenoid and back to the ECM is incomplete.The possible causes for this diagnostic code are listed:
The signal circuit from the ECM to the solenoids is open.
The return circuit from the solenoid is open.
The internal windings for the solenoid have high impedance.
The internal windings for the solenoid are open.System Response:The machine response is listed:
The lift linkage will not lower.
The lower detent coil will be disabled.
The implements will be disabled until the fault is corrected and the levers are centered.Note: All solenoid return lines for the solenoid are joined and the return lines are connected to contact J1-50 (wire J813-BK) of the implement ECM.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code is corrected.Note: Ensure that the diagnostic code is active and that the diagnostic code indicator is active.Test Step 1. CHECK THE SOLENOID.
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the solenoid with the diagnostic code from the harness.
Observe the ON/OFF status of the diagnostic code indicator.
At the harness connector for the solenoid, place a jumper wire between contact 1 (wire H714-OR) and contact 2 (wire J813-BK).Note: The approximate resistance of a proportional solenoid valve is from 6 to 12 Ohms.Expected Result:The diagnostic code indicator remains active.Results:
YES - The diagnostic code indicator remains active. The diagnostic code is active. The harness has failed or the ECM has failed. Proceed to Test Step 2.
NO - The diagnostic code indicator is inactive.Repair: The solenoid valve has failed or the connecting harness has failed. Repeat this test in order to verify the failure. Repair the solenoid or replace the solenoid. Repair the connecting harness or replace the connecting harness at the solenoid. Stop.Test Step 2. CHECK THE HARNESS.
Turn the disconnect switch to the OFF position.
Remove the jumper wire from contact 1 (wire H714-OR) to contact 2 (wire J813-BK).
Reconnect the solenoid valve to the harness.
Disconnect the harness from the ECM.
At the harness connector for the ECM, measure the resistance between contacts J1-50 (wire J813-BK) and contact J1-49 (wire H714-OR). Note: The approximate resistance of a proportional solenoid valve is from 6 to 12 Ohms.Expected Result:The resistance is greater than 5000 Ohms with no continuity.Results:
YES - Resistance is greater than 5000 Ohms (no continuity).Repair: The harness circuit has failed. Wire H716-WH is open in the harness between the ECM and the solenoid valve, or the wire to the solenoid valve is open. Repair the harness or replace the harness. Stop.
NO - Resistance is from 6 to 12 Ohms.Repair: The harness circuit resistance is correct. It is unlikely that the ECM has failed. Exit this procedure and perform this troubleshooting procedure again. Also ensure that the diagnostic code indicator is active for this diagnostic code. If the cause is not found, replace the ECM. See Testing